John Terry has launched an impassioned defence of his much-criticised form this season as he prepares to lead his Chelsea side out at Liverpool this weekend on a potentially decisive afternoon in the title race.

The centre-half, stripped of the England captaincy by Fabio Capello in February following revelations over his private life, has seen his every mistake scrutinised this term. There were high-profile errors against Everton and Manchester City, and a tackle on James Milner in the recent FA Cup semi-final against Aston Villa which prompted a furious reaction from Martin O'Neill, before Terry was sent off for two bookable offences in Chelsea's defeat at Tottenham Hotspur earlier this month.

Yet the 29-year-old, who will return to the starting line-up for Sunday's pivotal game at Anfield with his side a point clear of Manchester United at the top, insisted he was happy with his displays for club and country. "I'm totally fine with my form," he said. "For England, I think my performances have been very good right through the campaign and, as for Chelsea, I missed one game through suspension against Stoke last week but I think my form is fine, contrary to what everyone else is saying.

"I've played in almost every game for Chelsea this year, apart from one in the Carling Cup away to Blackburn and the suspension last week. If I'm going to play 50 or 60 games I'm expected to have one, two or three bad games, that's standard, you are not going to play well every game. Not even Wayne Rooney and Lionel Messi can do that. As a player it's inevitable you do have bad games, and it's all about how you respond. And I think I've responded well."

Terry has drawn support from his manager, Carlo Ancelotti, and club-mates in recent weeks with the Italian suggesting too much was being made of the occasional error. "I think that people are looking too much at his performances," the Chelsea manager said in the wake of the defeat at White Hart Lane. "He is doing very well. He has had a fantastic season. Maybe sometimes he has had problems and not played so well, but you have to look at the whole season." Frank Lampard described his team-mate's form as "brilliant", adding: "It's fashionable to have a pop at the top of the tree, but at Chelsea we know his true value."

Yet his uncharacteristic errors have left Terry open to criticism, with the BBC pundit Alan Hansen claiming recently that the defender had endured an "indifferent season". "When players like Alan talk – players who have achieved a lot in the game and have been defenders as well – I stand up and listen, even though I am my own worst critic," said Terry, who was launching England Football Day, the FA's call to the nation to come together on 12 June to play, coach and celebrate football. "But I feel I am playing well."